(a) Field of the Invention
The present invention relates to a liquid crystal display, and more particularly, to a vertically-aligned liquid crystal display in which pixel regions are divided into small domains.
(b) Description of the Related Art
In a liquid crystal display (LCD), liquid crystal material is injected between an upper substrate, on which common electrodes and a color filter are formed, and a lower substrate, on which thin film transistors and pixel electrodes are formed. A voltage of a different potential is applied to the pixel electrodes and common electrodes to form an electric field, thereby varying the alignment of liquid crystal molecules of the liquid crystal material. In this way, the transmittance of incident light is controlled to enable the display of images.
However, a serious drawback of LCDs is the limited viewing angle. Various methods and configurations have been developed to overcome this problem. Among such methods, the liquid crystal molecules are aligned perpendicularly to the upper and lower substrates, and either a predetermined aperture pattern or protrusions are formed on the pixel electrodes and the opposing common electrodes.
By forming the aperture patterns on the pixel electrodes and common electrodes, a fringe field is generated. Using the fringe field, a slanting direction of the liquid crystal molecules is controlled to increase the viewing angle. When protrusions are formed on the pixel electrodes and common electrodes, on the other hand, an electric field distorted by the protrusions is used to control the slanting direction of the liquid crystal molecules. In an alternative method, aperture patterns are formed in the pixel electrodes provided on the lower substrate and protrusions are formed on the common electrodes provided on the upper substrate. Using a fringe field generated by the aperture pattern and protrusions, the slanting direction of the liquid crystal molecules is controlled to form domains.
However, in the above methods, dark portions where light is not transmitted appear in areas where the aperture patterns and protrusions are formed. As a result, a large area occupied by the aperture patterns and protrusions may reduce the brightness of the LCD panel. If the number of aperture patterns and protrusions is reduced in an attempt to remedy this problem, the ability to control the slanting of the liquid crystal molecules is reduced and results in an uneven alignment. Hence, the texture generated by the uneven alignment extends over relatively large areas and reduce the brightness and overall picture quality.